Conventional means of testing for alignment errors or errors caused by thermal distortion or turbulence within a laser or the optical train associated with it is the use of a diffraction grating etched on a mirror surface or a dichroic beam splitter. Either of these sampling devices deflects a low power sample beam from the relatively high powered output beam and directs the sample beam onto a detection device such as a Hartmann Sensor. The Hartmann Sensor, which is conventional in the art, analyzes the sample beam to determine the tilt of the phase front, focus/de-focus and time dependent errors. Conventional analyzing means such as a programmed digital computer accept as input the signals from the Hartmann Sensor and control the mirrors--either controlling the tilt of a rigid mirror or controlling the surface configuration of a deformable mirror as is known in the art.